The invention relates to precision seed spacing drills of the type including a casing of cylindrical overall shape, inside of which is rotatably mounted on a horizontal shaft, a flat distributor disc equipped with circumferentially-spaced holes which have dimensions smaller than the seeds. The distributor disc separates a seed container from a suction device so that the holes are subjected to suction or a depression for retaining the seeds taken up from the container during at least a part of the angular travel of the disc. A deflector member is provided to eliminate double seeds. A device for discharging the seeds is also provided.
Such a distributor is described in French Patent 2,630,288 of the assignee company; more particularly, the embodiment of FIG. 6 which represents a flat disc without fins interacting with a notched selector member.
In this embodiment, the flat disc includes a single circular row of holes which are subjected to the depression until they come close to the discharge device.
If one wishes to obtain even precise sowing, particularly without double seeds and without gaps, then it is necessary to limit the rotational speed of the distributor discs. As a result, in the case where seeds are to be sown densely in rows, the working speed must be low. Thus, for example, for sowing soy bean seeds, for a distance of 5 cm between plants, the working speed is currently limited to 6 km/h, if one wishes to obtain a crop without gaps or double seeds.
This is why one tends to use discs including a maximum number of holes, but the number of holes is limited by the dimensions of the distributor disc.
For high-density sowing, such as the sowing of soy bean seeds, the maximum number of holes allowed on the circumference of the distributor disc does not allow for fast work while maintaining a sufficiently slow rotation.
The present invention therefore aims to provide a distributor for a seed spacing drill of the abovementioned type which makes it possible to obtain a high sowing density while keeping the speed of the distributor disc to a sufficiently slow value and allowing rapid work.
To this end, the subject of the invention is a distributor for a seed spacing drill of the abovementioned type which is especially noteworthy in that the flat distributor disc includes at least two coaxial circular rows of holes which are subjected to a depression until they come close to a discharge device, and in that a deflector is located, relative to the distributor disc, so as to act only on the seeds located in the holes of the outermost row.
The elimination of double seeds takes place directly via the selector consisting of the deflector member for all the holes of the outermost row. With regard to the holes of the other rows, this elimination takes place by means of the seeds fixed to the holes of the outermost row. By virtue of this arrangement, it is still possible to obtain even sowing, particularly without double seeds, with a high density without increasing the rotational speed of the distributor disc.
According to one embodiment of the invention, the flat distributor disc includes two coaxial rows of holes, the holes of one row being angularly offset relative to the holes of the other row.
According to another characteristic of the invention, the diameter of the holes of the row close to the deflector is preferably greater than the diameter of the holes of the other rows.
By virtue of this arrangement, the number of double seeds on the holes of the rows other than the row on which the deflector member acts directly is limited.
According to another characteristic of the invention, the distance between two adjacent holes of two adjacent rows is at most equal to twice the mean diameter of the seeds to be sown. Advantageously, this distance lies between approximately one and one and a half times the mean diameter of the seeds to be sown.
By virtue of this arrangement, the indirect action of the deflector member is optimal.